User's Guide

Commands: Write Data Buffer (3Bh) Page 165
Command Descriptor Block Field Descriptions
The following table provides descriptions of the CDB fields.
Field
Name Bytes Bits Description
MODE 1 0-2 If MODE=0, only the data buffer is loaded. If MODE=2, data is loaded
starting at the offset location specified by ADRS. If Mode=5, the data is
transferred to the controller's flash EEPROM, and the firmware is
restarted.
For mode 4 and 5 the total transfer length must be A00000h with a starting
offset of zero. Multiple mode 4 commands can be issued to transfer the
data. The last micro code transfer mode must be mode 5 to initiate
transfer of the micro code to the Flash memory. Transfer lengths of zero
are valid on any command.
Buffer
ID
2 Only Buffer ID 0 is valid
ADRS 3-5 If MODE=2, 4, or 5, then ADRS is the offset where data loading begins.
Otherwise, ADRS should be all zeros.
Byte
Transfer
Length
6-8 The Byte Transfer Length specifies the maximum number of bytes
transferred to the drive. If MODE=0, it contains a four-byte header; thus,
the data length to be stored in the buffer of the drive is Byte Transfer
Length minus 4. If MODE=2, 4, or 5, the header is not used.
A Byte Transfer Length of zero indicates that no data are transferred. This
condition is not an error. It is not an error to request a Byte Transfer
Length less than the Available Length (reported by the READ DATA
BUFFER command).
If MODE=0, the initiator should ensure that the Byte Transfer Length is not
greater than 4 plus the Available Length that is returned in the header of
the READ DATA BUFFER command. If the Byte Transfer Length is
greater than the Available Length plus 4, the drive returns a Check
Condition status with a Sense Key of Illegal Request.
WRITE DATA BUFFER Data Header
The following table shows the layout of the data header Block.
Byte
Bits
7 6 5 4 3 2 1 0
0 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
2 0 0 0 0 0 0 0 0
3 0 0 0 0 0 0 0 0